def _sun_coor(julian):
"""Return the sun's coordinates.
Parameters
----------
julian : np.ndarray
1-D array containing Julian times in the J2000 epoch.
Returns
-------
Coordinate
Coordinate object containing the sun's position.
"""
ephem = pkg_resources.resource_filename(__name__, '../data/de421.bsp')
kernal = SPK.open(ephem)
ssb2sunb = kernal[0, 10].compute(julian)
ssb2eb = kernal[0, 3].compute(julian)
eb2e = kernal[3, 399].compute(julian)
e2sun = (ssb2sunb - ssb2eb - eb2e).T
SPK.close(kernal)
sun_coor = Coordinate(e2sun, "gcrs", julian)
return sun_coor
def test_single_position(self):
kernel = SPK(NAIF_DAF(open('de405.bsp', 'rb')))
x, y, z = kernel[0,4].compute(2457061.5)
# Expect rough agreement with a DE430 position from our README:
self.assertAlmostEqual(x, 2.05700211e+08, delta=2.0)
self.assertAlmostEqual(y, 4.25141646e+07, delta=2.0)
self.assertAlmostEqual(z, 1.39379183e+07, delta=2.0)
kernel.close()
